Explosive



Patented June 28, 1932 UNITED STATES PATENT OFFICE GEORGE BURKLEHOLDERER, 0F SCARSDALE, NEW YORK, AND LE ROY V. CLARK, OF

- PITTSBURGH, PENNSYLVANIA EXPLOSIVE No Drawing.

This invention relates to explosives and more particularly to liquidoxygen explosives.

In the use of liquid oxygen'explosives a suitable quantity of carbon orcarbonaceous material is placed in a bag and liquid oxygen addedthereto, the oxygen being absorbed by the carbon or other carbonaceousmaterial. The cartridges actually used in this manner may be ofconsiderable size and when they are to be used they are placed ordropped in a hole or bore to be exploded, with the detonating materialand the charge then tamped. In dropping the cartridge into a hole thereis considerablechance of tearing the bag or casing and if this occurs,the loose carbon, which is now used and which is highly charged withoxygen, is released in the form of a dust. As this charge is highlyexplosive, the risk of premature explosions is very great. In thepresent invention we propose to form an explosive in which the carbonparticles are boundtogether-and dustwill, therefore, not be created ifthe bag or casing istorn in dropping the cartridge into a hole, or inany other way. By binding the carbon particles together we may eliminatethe casing, but we prefer to use it to retard evaporation of theabsorbed liquid oxygen; We may, however, use a bag or casing of a muchlighter material than that heretofore employed and thus reduce the costof manufacture of the cartridge. v

We are aware of prior efforts to produce an explosive consisting ofcarbonaceous material having absorbed liquid air as an oxidizing mediumin which the carbonaceous material is bonded together to form asubstantially rigid structure. In the prior art with which we arefamiliar the carbonaceous material so employed has been in the form of apowder and has been molded in such manner that a non-porous structurewould be produced if special precautions were not exercised to giveorosity to the material. It has heretofore been proposed to mix thecarbonaceous material with an adhesive, sufficient liquid to form apaste and with a ferment, such as yeast or sodium bicarbonate. The pastymixture so formed is pressed and then baked until a rigid body isobtained, the action and ferment be- Application filed June 8, 1931.Serial No. 543,006.

ing relied upon to produce the necessary porosity.

We are also aware of prior efforts to produce liquid oxygen explosivesin the form of a rlgid body in which a material such as molasses is usedand dehydrated or partially dehydrated and mixed with powdered charcoalor carbon-black. We have found that a sufliciently porous, carbonaceousmaterial may be produced in the form of a cake or stick by using carbonsor carbonaceous material of a proper character and merely treating itwith suflicient binder to hold the particles together withoutsubstantiallydecreas ing the porosity of the carbon or carbonaceousmaterial. In our invention we specifically avoid the'production of apasty mass and subsequent moldin of this material in such form as wouldpro uce a non-porous body if such precautions were not taken to providefor the porosity of the cartridge. In carrying out our invention weemploy a carbon in granular form. If powdered carbon is mixed with abinder in liquid form, we have found that the resulting product does notpossess sufficient porosity.- We, therefore, employ what is commerciallyknown as Bugbird carbon whch we understand is produced in accor ancewith the Bugbird patents Nos. 1,706,871, 1,779,530 and 1,781,214.As-disclosed in these patents the carbonaceous material which we employpreferably. consists of granules or particles of suchsize that thedensity of the product is equal to about 0.25 to 0.35. The grainsof-carbon vary considerably in size, the largest being about one quarterinch in their longest dimension and the size of the granules'being suchthat about 25 per cent of the material will pass through I 'a 100 meshscreen. While the use of Bugbird set forth above in the production of asolid or molded cartridge having a high degree.

of absorption for liquid oxygen. In carrying out the invention thecarbonaceous material is mixed with a suitable binder. We may employ astarch solution for this purpose and purpose to use-a solutioncontaining from in loose form and substantially the same re sults havebeen obtained in impact tests to determine the sensitivity of theexplosive.

In practicing the invention on a commercial scale, a suitable binder,such as the starch solution set forth above, may be sprayed on thecarbon sufficiently to wet it and the carbon in this form filled intothe bags or casings in the usual filling machine. The cartridge may thenbe allowed to dry and the carbon will be sufiiciently'agglomerated toprevent dusting. When the casing is employed with the cartridge it isnot necessary that the cartridge be baked or oven dried to a hard andsolid product and better results are obtainedif only the usual pressurenow applied in filling bags is used so that the carbon particles aremerely bonded together sufliciently to prevent dusting if the bag tearswhen it is dropped into a drill hole. In the commercial use of liquidoxygen explosives substantially 15 per cent of moisture may be retainedin the carbon and we therefore propose to avoid drying of the cartridgeto complete dryness.

In lace of starch any of the usual binders may e employed. The bindermust be chosen in consideration of its adhesiveness, its ability to beused inconnection with the usual filling machine for liquid oxygencartridges and its ability to dry or set quickly. It must also becapable of producing a car.- tridge having sufficient resistance tocrushing and it must not adversely affect the ability of the carbon orcarbonaceous material to absorband retain liquid oxygen. Other binderswhich may be used in place of starch are organic binders, such asgelatin and gluten, various glues and pastes, various sugar orsaccharine compounds, resins and gums, such as natural or syntheticresins, gum arabic, phenol and the like, cellulose plastics andlacquers, rubber, waxes and petroleum products, such'as tars, pitch andparaflin.

We may also employ inorganic binders, such as sodium silicate,plaster'of Paris and the like.

As stated, the essential feature of the invention is the use of carbonor carbonaceous material in granular form whereby a molded product canbe formed by the use of a limited quantity of a binder in which theability of the carbon or carbonaceous material to absorb and retainliquid oxygen is not seriously impaired. By the use of such a binder andjust suflicient pressure to hold the particles together to preventdusting in case of tearing of the cartridge case or bag in lowering thecartridge into a drill hole, the hazard of carbon dust suspended in anatmosphere of oxygen is eliminated.

We claim:

1. A liquid oxygen explosive material comprising carbonaceous materialin granular form and a binder in an amount su'liicient to I agglomeratethe carbonaceous material Without appreciably ailecting its porosity.

2. A cartridge for liquid oxygen explosives comprising a granularcarbonaceous material and a binder in an amount sufiicient toagglomerate the carbonaceous material without appreciably ailecting itsporosity, said cartridge containing approximately 10 per cent of water.

3. A cartridge for liquid oxygen explosives comprising granularcarbonaceous material and a starch binder in an amount suiiicient toagglomerate the carbonaceous material Without appreciably affecting itsporosity.

4. A cartridge for liquid oxygen explosives 7 that substantially 25 percent will pass through a hundred mesh screen, and a binder in an amountsuflicient to agglomerate the carbonaceous material without appreciablyaffecting its porosity, said cartridge contain-- ing substantially 10per cent of moisture.

7. The herein described process which comprises applying a binder inliquid form to granular carbonaceous material in an amount suflicient toagglomerate the carbonaceous material but insufficient to appreciably,reduce its porosity, and pressing the material into a cartridge.

. 8. The herein described process which comprises applying a binder inliquid form to granular carbonaceous material in an amount suificient toagglomerate the carbonaceous material but insuflicient to appreciablyreduce its porosity, pressing the material into a cartridge and drgingthe cartridge d) a moisture content of su stantially 10 per cent.

9. The herein described process which comprises applying a starchsolution to granular carbonaceous material in an amount suificient to aglomerate' the carbonaceous material but insu cient to materially reduceits porosity and then pressing the carbonaceous material into acartridge.

10. The herein described process which comprises applying an organicbinder in a liquid form to carbonaceous material in an amount suificientto agglomerate the carbonaceous material but insuflicient to materiallyreduce its porosity and then pressing it into a cartridge.

' 11. The herein described process which comprises applying an inorganicbinder in a liquid form to carbonaceous material in an amount suflicientto agglomerate the carbonaceous material but insufiicient to materiallyreduce its porosity and then pressing it into a cartridge.

12. The herein described process which comprises applying a binder inliquid form to granular carbonaceous material in an amount sufficient toagglomerate the carbonaceous material but insufiicient to materiallyreduce its porosity and then filling the material into a cartridgecasing to cause agglomeration of the material.

In testimony whereof we aifix our signatures.

GEORGE BURKLE HOLDERER. LE ROY V. CLARK.

